PARIS (AP) — A high-ranking French health official says a first case of sexually transmitted Zika virus has been diagnosed in France on a non-pregnant woman.

Francois Bourdillon, the director general of the French Institute for Public Health Surveillance, told BFM television that "the patient had not travelled, her companion was returning from Brazil" where he was infected with the Zika virus. He says both are "doing well."

Zika is primarily spread by mosquito bites, and transmission through sex is considered rare.

In the United States, the Centers for Disease Control and Prevention said last week two cases of sexual transmission of Zika from male travelers to their sexual partners have been confirmed and four others are probable amid an investigation into 14 potential cases.